Experimental Study on the Mitigation of Backdraft in Compartment Fires with Water Mist

Abstract

In this paper, the results of a reduced-scale experimental test series using water mist to mitigate backdraft in compartment fires are presented. This reduced-scale compartment (1.2 m 0.6 m 0.6 m)was fitted with a variety of end opening geometries: middle-slot, upside-slot, downside-slot, door, window and vertical middle-slot, and ceiling opening geometries: slot and window. Water mist was generated by a downward-directed pressure nozzle that was operated at pressure of 0.2 MPa. Experimental variables included fuel flow rate, burn time, water mist injection time and mass, and opening geometries. Histories recorded prior to backdraft included upper layer temperatures, lower layer temperatures, and species concentration for oxygen, carbon dioxide and carbon monoxide. Data collected to quantify the backdraft included opening gas flow velocities and compartment pressures. The experimental results show that water mist is an effective mitigating tactic that is able to suppress backdraft in compartment fires primarily by means of diluting the gas in the compartment and reducing total hydrocarbons mass fraction, rather than by a thermal mechanism of cooling. KEY WORDS: backdraft, compartment fire, water mist.

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References

Bukowski, R.W. (1995). Modeling Backdraft: The Fire at 62 Watts Street, NFPA J., 89: 85-89.

Fleischmann, C.M. (1994). Backdraft Phenomenon, National Institute of Standards and Technology, USA, NIST-GCR-94-646.

Fleischmann, C.M. and McGrattan, K.B. (1999). Numerical and Experimental Gravity Currents Related to Backdrafts, Fire Safety J., 33: 21-34.

Fleischmann, C.M. , Pagni, P.J. and Williamson, R.B. (1994). Quantitative Backdraft Experiments. In: Proceedings of the Fourth International Symposium on Fire Safety Science, pp. 337-348, International Association for Fire Safety Science, Canada.

Fleischmann, C.M. , Pagni, P.J. and Williamson, R.B. (1994). Salt Water Modeling of Fire Compartment Gravity Currents. In: Proceedings of the Fourth International Symposium on Fire Safety Science, pp. 253-264, International Association for Fire Safety Science, Canada.

Weng, W.G. , Fan, W.C. , Qin, J. and Yang, L.Z. (2002). Study on Salt Water Modeling of Gravity Currents Prior to Backdrafts Using Flow Visualization and DPIV, Exp. Fluids., 33: 398-404.

Bolliger, I.B. (1995). Full Residential-scale Backdraft, Fire Engineering Research Report 95/1, University of Canterbury, New Zealand.

Gojkovoc, D. (2001). Initial Backdraft Experiments, Report 3121, Lund University, Sweden.

Gottuk, D.T. , Williams, F.W. and Farley, J.P. (1997). The Development and Mitigation of Backdrafts: A Full-Scale Experimental Study. In: Proceedings of the Fifth International Symposium on Fire Safety Science, pp. 935-946, International Association for Fire Safety Science, Australia.

10.

Gottuk, D.T. , Peatross, M.J. , Farley, J.P. and Williams, F.W. (1999). The Development and Mitigation of Backdraft: A Real-Scale Shipborad Study, Fire Safety J., 33: 261-282.

11.

Williams, F.W. , Farley, J.P. , Peatross, M.J. and Gottuk, D.T. (1997). 1995 Class B Firefighting Doctrine and Tactics: Final Report, Naval Research Laboratory, USA, NRL/MR/6180-97-7909.

12.

Weng, W.G. , Fan, W.C. , Wang, Q.A. and Yang, L.Z. (2002). A Model of Backdraft Phenomenon in Building Fires, Prog. Nat. Sci., 12: 131-135.

13.

Weng, W.G. and Fan, W.C. (2001). Catastrophe Behavior of Backdraft in Compartment Fires. In: 5th Asia-Oceania Symposium on Fire Science and Technology, Newcastle, Australia.

14.

Kathy, A. and Notarianni, P.E. (1994). Water Mist Fire Suppression Systems. In: Proceeding of Technical Symposium on Halon Alternatives, pp. 57-64, Society of Fire Protection Engineers and PLC Education Foundation, Knoxville, TN.

15.

Albert, R.L. (1993). Incentive for Use of Misting Spray as a Fire Suppression Flooding Agent. In: Proceedings of Water Mist Fire Suppression Workshop, pp. 31-36.

16.

Mawhinney, J.R. and Eng, P. (1993). Engineering Criteria for Water Mist Fire Suppression System. In: Proceedings of Water Mist Fire Suppression Workshop, pp. 37-73.

17.

Quintiere, J.G. , Steckler, K. and Corley, D. (1984). An Assessment of Fire Induced Flows in Compartments, Fire Sci. and Tech., 4: 1-14.

18.

McCaffrey, B.J. and Heskest and, G. (1976). A Robust Bidirectional Low-Velocity Probe for Flame and Fire Application, Combust. Flame, 2: 6125-6127.